Borehole explosive charge



2 l zi. T M. v`..u u b l wm NL 1, m w. 7 m 9 ...w .l A 2 m a QW cf.. 2. RM WMJ www a E E. /mh .l y B m fm). f H IM .m K M www@ s m m. fam) X \/\.1 a I J E 1. 9 E E m M n s O B 8 Filed Nov. 8, 1945 Patented Dec. 20, 1949 UNITED STATES PATENT OFFICE BOREHOLE EXPLOSIVE CHARGE Edwin J. Shimek, Dallas, Tex.

Application November 8, 1945, Serial No. 627,316

(Cl. IGZ-21.8)

6 Claims.

This invention relates generally to bore hole explosive charges and will be found particularly useful in seismographic exploration.

In seismographic exploration it is now customary to lower an explosive charge into a bore hole by means of loading poles of a suitable nature to the depth desired by the field technicians. The charge and pole string are so connected that after the charge has reached a predetermined position in the bore hole the loading poles may be detached from the charge and withdrawing from the bore hole. The charge is then exploded by means of conventional equipment including conductors extending down into the bore hole and connected to the charge.

The loading pole is usually connected to the explosive charge by a device which releases the charge when the loading pole is given an abrupt vertical pull. Serious accidents have occurred by reason of the fact that the explosive charge does not remain at the predetermined depth at which it is detached from the loading pole. At times it is moved upwardly by the flow of subsurface water into the bore hole, by the buoyancy provided by the mud column, and at other times it is moved upwardly by the ring line when the latter becomes temporarily entangled with the loading poles as the latter are withdrawn. Whatever may be the cause of the upward movement of the explosive charge the fact is that it does at times move upwardly to a point at or near the surface of the earth and when exploded endangers the lives of the field technicians.

Aside from the danger to the eld technicians, in seismograph exploration it is of utmost importance that the charge be exploded at a predetermined and positively known depth because if a charge is exploded elsewhere in the bore hole, a result is obtained which is undesirable. confusing. and misleading to the field and oilice technicians. For reasons well known to those skilled in the art, it is essential that the charge be exploded at a predetermined and known depth.

The general object of this invention is to provide an explosive charge which may be inserted in a bore hole a predetermined distance and which is provided with means to hold it in that position, movement of the charge outwardly of the bore hole and consequent danger to field technicians and erroneous computations being eliminated.

Other objects will hereinafter appear.

'I'he preferred embodiment of the invention is illustrated in the accompanying drawings in which Fig. 1 is a vertical section of a bore hole with the equipment therein;

Fig. 2 is a side elevation of an explosive partially in its tube;

Fig. 3 is a fragmentary vertical section of the tube;

Fig. 4 is a side elevation of two explosives connected by a single tube;

Fig. 5 is a fragmentary vertical section of the explosive;

Fig. 6 is a fragmentary vertical section of that part of the tube which is adapted to form wall engaging ngers to prevent movement of the tube in the bore hole;

Fig. 7 is a fragmentary sectional elevation disclosing the initial distortion of that part of the tube illustrated by Fig. 6;

Fig. 8 is a fragmentary sectional view illustrating the ultimate distortion of the same; and

Fig. 9 is a side elevation of the tube with the wall engaging fingers in their extended positions, some of said ngers being removed to better illustrate the construction thereof.

Fig. 10 is a diagrammatic view illustrating the internal thread of the tube as substantially continuous when the sections of the tube 'I are moved to positions adjacent each other.

Referring to Fig. 1 of the drawing, the bore hole is indicated at I, the explosive charge at 2, the Wall engaging means at 3, the loading pole string at 4, the releasable device to connect the loading pole string 4 with the charge 2 at 5, and the firing line at 6.

It is now customary to lower the charge 2 by means of the loading pole string 4 to a predetermined position in the bore hole I. The loading pole string 4 is then jerked upwardly to cause the device 5 to release the charge 2 and the loading pole string 4 is then withdrawn from the hole, the charge 2 `being held from downward movement from the predetermined position by the firing line 6.

The explosive charge now in use does not embody the wall engaging means 3 shown in Fig. 1 and by reason thereof the explosive charge 2, as hereinabove stated, is frequently moved by one force or another upwardly in the bore hole to a position at or near the surface of the earth, with the dangerous and objectionable results above stated This invention includes the provision of wall engaging means to positively prevent such upward movement after the explosive charge has reached the predetermined depth.

It will, of course, be understood that the bore hole I may be of a depth such that the bottom and may rest upon the bottom. However', this'is f wall of the'bore hole and positively prevent'uo-y f 1 ward movement ofthe explosive charge.

. f rOrdinarily the tube 'i is made of waxed pasteL not a requisite for theproper functioning of the charge locating means. :Referring to Figs.l 2and3, the tube'is indicated by the numeral 1 and its internal; thread bythe f f numeral 8, the explosive charge by the numeral board ior the like. sof that it is rrelatively lfrangible and the explosive -charge'may be removed by a force exceeding the forces which normally tend to movethe explosive charge upwardly. -But it will seldombe desired to remove the chargefrom'the f f f 9 and its. externalthread by the numeraly l bore hole in seismographic operations, the prac- In Fig. 4l,` two explosive chargesS 'and one connecting tube 'I are shown, the two explosive event,in orderto avoid possible injury to `the yfield technicians.

charges 1 9f being. threaded. into yopposite Aends of the tube 1.

Iny Fig. 5y the explosive charge 9 may include a Wrapper 9a and. explosive mixture 9b..' f

- In Fig.` 6` the -tube is shown as having .internall annular grooves II and I2, the distance between i these groovesy being. approximately equal. to the. pitch of the threads 8, orthis dstancema'y'be= varied so that the variable distance is approximately an integral `multiple of the pitch of. threads n -8-. Between these'internal annular grooves' II and f the fingers a hereinafter referred ftowill; te ydi-y rected outwardly and in the direction of the groove? f I2,y said direction being routwardly of the bore :nlewhe h .x1 o n t e e p osve Charge 1s owered here .its initial length =or collapse in. catcher loperat;

ing position. And so if the` eld technicianl does tice being gto explode the charge in the hole Ain .any

f f While the .charge is being loaded intoy the bor `hole the flexible ngers are `deflected. 'inwardly along the tube and present little additional cross vsectional area tothe completefcharge.. In those holes which are not cleank andl are loaded only f f lwith difiiculty the use of the catcher neither iis .desired nor need it be'used, as described hereinafter.

It will be noted that the grooves II, I2 and. I3

. and the slits A3a, the .latter ofwhich as hereinafter stated may be :out to a point immediately ad-y ,I2l is external annular grooves I3, which is closer `to the groove IZthanit is -to thegroove lI I so that in so that outward movement is prevented; `It

, will,y of course, be unclerstcodthat .this external gro-ove; I3 may be cut atv a point equidistant from the internal grooves I! and I2 so that the fingers `3 ywill extend radially outwardly at substantially a the endsiof the lingers 3is 'a function of the Aratio jacent the exterior surface, do not objectionably rweaken the tube l.l Additionally, the two movable parts ofthe tube, `being, threaded'on the charge,

would have to rotate withrespect to each other,

yor strip the threadbefore the tube could change not wish tomake use of the `lingers 3 in any given instancethe tube y'l is: quite strongy enough to be f of the distance between external'groove`13 and" internal groove I2 .to the distance between external grooveIEand'internal groove -I I'. f I

Referring further to Fig. 6, that part of the tube 'I intermediate the internal grooves II and I2 has axially disposed circumferentially spaced slits 3a to form the fingers 3 when that part of the tube in which the internal groove II is cut is moved toward that part of the tube in which the internal groove I2 is cut, as will hereinafter appear.

Referring now to Fig. 7, this gure illustrates the bending of the tube 1 at points adjacent the internal annular groove I I, the external annular groove I3 and internal annular groove I 2 during the initial movement toward each other of the sections of the tube 'I in which the grooves I I and I2 are cut.

Fig. 8 illustrates the bending of the tube adjacent the grooves II, I3 and I2 at the completion of the ultimate movement of the sections of the tube I having the grooves II and I2 toward each other. It will be noted that after such ultimate movement the internal thread 8 of the tube 'I is then substanially continuous.

Fig. 10 illustrates diagrammatically the thread 8 as substantially continuous when the sections of the tube are adjacent each other.

Referring to Fig. 9, this gure illustrates the exterior appearance of the tube I after the ultimate movement of the sections of the tube toward each other. It will be obvious from this figure that the fingers 3 have been moved outwardly into a position in which they will engage the wall of the hole (as also illustrated by Fig. 1) and if the usual forces tend to move the explosive charge upwardly the ngers 3 will tend to dig into the threaded upon theexplosives without ruptureq The .tube rIniaybe nrstr collapsed by moving the opposite endsgtoward eachother and then threaded upon a single charge while heldin the A.collapsed.positionsincethe internal thread is `then f substantially continuous; 'or the 'collapsed' tube may be threaded upona very short length yoffexplosive; or if. desired, two explosives may be threaded into a collapsed tube; or a series of explosives and collapsed tubes may be utilized.

The depth of the grooves II, I2 and I3 in tube 1 may be varied depending upon the material of which tube 'I is made. The depths illustrated are satisfactory when the tube I is made of pasteboard or the like. The slits 3a may be cut entirely through the tube 1 or if preferred to a point just beneath the exterior surface of the tube 1. These and other changes will be apparent to those skilled in the art, the invention not being lim- Ited to the preferred embodiment herein disclosed.

Having described my invention, I claim:

1. A bore hole explosive charge tube having an internal thread, said tube having two sections movable out of their normal positions to predetermined relative positions, the internal thread of said tube being substantially continuous when said sections are in said normal and relative positions, and that part of said tube between said sections being so constructed that when said sections are moved to said relative positions said part is moved outwardly into a bore hole wall engaging position.

2. A bore hole explosive charge including an explosive having external threads, a tube on said explosive and having internal threads engaging the threads of said explosive, said tubingl having circumierentially spaced axial slits, axially spaced internal annular grooves adjacent the ends of said axial slits, and an external annular groove between said internal annular grooves, those portions of said tube on the outside of said internal annular grooves being movable toward each other to cause those portions of said tube dened by said axial slits to move outwardly and to form lingers to engage the wall of the bore hole to prevent movement of said explosive charge in said bore hole, said internal annular grooves being so spaced that when said portions of said tube are moved toward each other the internal thread of said tube is substantially continuous.

3. A bore hole explosive charge including an explosive having external threads, a tube on said explosive and having internal threads engaging the threads of said explosive, said tubing having circumferentially spaced axial slits, axially spaced internal annular grooves adjacent the ends of said axial slits, and an external annular groove between said internal annular grooves, those portions of said tube on the outside of said internal annular grooves being movable toward each other to cause those portions of said tube defined by said axial slits to move outwardly and to form fingers to engage the wall of the bore hole to prevent movement of said explosive charge in said bore hole, said internal annular grooves being so spaced that when said portingof said tube are moved toward each other the` internal thread of said tube is substantially continuous, said external annular groove being closer to one of said internal annular grooves than to the other to cause said lingers to be projected in the direction in which movement of said explosive charge is to be prevented.

4. A casing adapted for use in lodging an explosive charge within a bore hole comprising a tube, internal annular grooves adjacent the ends of the tube, an external annular groove in the tube intermediate the internal grooves and axial slits spaced circumferentially about the tube, said slits extending between the internal grooves, whereby, when the tube is collapsed by axial movement of the end portions toward each other, the slitted portion is expanded radially, thus providing a container suitable for retaining an explosive charge and wall engaging fingers.

5. A casing adapted for use in lodging an explosive charge Within a bore hole comprising a tube having annular weakened portions on its internal surface adjacent the ends of the tube and also having an annular weakened portion on its external surface intermediate the internal weakened portions, the wall of the tube also being weakened along longitudinal lines which extend between the internal weakened portions, whereby when the tube is collapsed by axial movement of the end portions toward each other, the material between the internal weakened portions is expanded radially to form wall-engaging iingers.

6. A bore hole explosive charge tube having a plurality `of spaced longitudinal slits in its wall with the ends of said slits terminating short of the ends of the tube, the material between said slits being displaced radially outwardly and folded upon itself to form wall engaging ngers when the tube is collapsed by axial movement of the end portions toward each other.

EDWIN J. SHIMEK.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 156,673 Peck Nov. 10, 1874 1,641,483 Greene Sept. 6, 1927 1,875,583 Fox Sept. 6, 1932 2,083,975 Y Armstrong June 15, 1937 2,222,405 Cox et al Nov. 19, 1940 2,345,654 Bowman Apr. 4, 1944 

